net : stmmac: rgmii clock was not setting to low

On Link down event the rgmii clock is not setting to low speed.
Rgmii clock should change to 50Mhz when Link down event
is received.

Change-Id: I62da6683642ee5625aadc793bb8ea72e37e60b37
Signed-off-by: Karthik Rudrapatna <krudrapa@codeaurora.org>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -295,8 +295,14 @@ static inline u32 stmmac_rx_dirty(struct stmmac_priv *priv, u32 queue)
  */
 static inline void stmmac_hw_fix_mac_speed(struct stmmac_priv *priv)
 {
-	if (likely(priv->plat->fix_mac_speed))
+	if (likely(priv->plat->fix_mac_speed)) {
-		priv->plat->fix_mac_speed(priv->plat->bsp_priv, priv->speed);
+		if (priv->phydev->link)
+			priv->plat->fix_mac_speed(priv->plat->bsp_priv,
+						  priv->speed);
+		else
+			priv->plat->fix_mac_speed(priv->plat->bsp_priv,
+						  SPEED_10);
+	}
 }
 
 /**
@@ -854,6 +860,7 @@ static void stmmac_adjust_link(struct net_device *dev)
 			priv->oldlink = true;
 		}
 	} else if (priv->oldlink) {
+		stmmac_hw_fix_mac_speed(priv);
 		new_state = true;
 		priv->oldlink = false;
 		priv->speed = SPEED_UNKNOWN;